Control valve



Feb. 1o, 19131. s, a gm 1,191,613

CONTROL VALVE Filed July 15'. 1929 Patented Feb. 10, 1931 PATENT GFFECE SAMUEL B. CLAY, OF ST'. LOUIS, MISSOURI CONTROL vALvE Application med July 15,

This invention relates to a valvefthat is intended to be used for controlling or governing the operation of'a piston or similar part that is moved in opposite directions by an operating medium under pressure, or moved in onedirection by an operatingmedium under pressure, and moved in the op- Q positedirection by a 'diierent means, such, for example, as a spring.

One obJect of my invention 1s to provide an' inexpensive control valve of simpleV design and rugged construction, that is equipped With a single valve elementvvhich Y governs the admission and exhaust of an op- 5 the valve.

5 opposite directions are effected by reducing,

lerating medium to and from the device with Whichthe valve is associated, or which the valve controls. y

Another-Objectis to provide an eilicient control valve of simple design, that is equipped with aV reciprocating valve elementk that governs the admission and exhaust of an operating medium to and fronithe opposite ends of the cylinder" which contains ythe v piston Whose movementsare controlled' by VAnother object is to provide aV control valve that Will not Wear rapidly or become leaky, and which is Vof such' design that the lpressure of the operating medium governed by the valve is used to edect a change in the position of the valve element. y

And still another object is to. provide ,a control valve that is equipped with a reciproeating valve element Whose vmovements in the pressure in the opposite ends of the casing of the valve in which said valve element is positioned. Other objects and desirable features of my invention Will lie-hereinafter pointed out. Y n f p Y Figure 1 is a front elevational view of a control valve constructed in accordance with my invention.

Figure 2 is an end View of said valve. v Figure 3 is a longitudinal sectional view of said valve; and Y Figure 4 is a transverse sectional view, talrenon the linee-#4 of Figure 3.

In the acconnoanyingdrawings which illustrate the preferred form of my invention,

1929. Serial No. 378,452.

A designates the casing of the valve, which is preferably of cylindrical form, B designates a valve element of the piston type or spool type, which is reciprocatingly mounted in said casing, C designates a supply pipe Which contains an operating medium under pressure, such, for example, as compressed air, having one of its ends attached to the valve casing and its opposite end communicating with the source of supply of the operating medium, Dand E designate supply ports in the valve`4 casing, herein shown as pipes that lead Vfrom the valve casing to the opposite ends of'a cylinder (not shown) Which contains the, pistonr Who-se movements are controlled by the valve, and'D and E designate exhaust ports in the casing A 0i the valve.

constructed that the operating medium sup F plied to the valve by the pipe C Will normally exert a substantially equal pressure on opposite sides or opposite ends of said valve element B. v.ln the form of my invention herein shown the supply pipe C is attached to a nipple l threaded into the cylindrical Wall of the valve/'casing A and having its inner end portion positioned in an elongated slot 2 in the cylidricalside Wallk oi the valve element B, said slot 2 beingpreferably so proportioned that thenipple l Will serve as a stop that co-operates with the slot 2 in the valve element to limit the movement of said valve element in opposite directions and also to prevent the valve element B from rotating or turning' in the valve casing. f

rlhe operating medium which the valve controls is admitted to the interior oi the valve element B by the supply pipe C, and said operating medium then escapes through a port 3 inthe valveelement into one or the other of the pipes D or E, depending upon the position of said lvalve element. the port 3 beingformed. in the cylindrical portion of the valve element B. midway the opposite y ends of said valve element, as shown clearly lili! that when said valve element is in one of its extreme positions, the groove D2 will register with and establish communication between the pipe D and the exhaust port D in the valvecasing,-and when said valve element is in its other extreme position, the groove E2 will register with and establish communication between the pipe E and the exhaust port E in the valve casing.

In order that the operating medium which the pipe C admits to the interior of the valve element B may enter the opposite ends of the valve casing A, and thus normally exert a` substantially equal pressure on opposite sides or opposite ends ofthe valve element, small leak holes orportsl are formed in the end walls of the valve element B, and Yin order that this balanced condition in pressure may he maintained in the valve casing, even when the valve element B is at the end of its stroke in either direction, the heads or end walls A of the valve casing are provided with recesses These recesses areso proportioned and arranged'that when the valve element B is ineither of its extreme positions, with one ent of same touching` against the opposed end Wall of the valve casing, there will be a space or chamber beyond said end which communicates with YVthe interior of the valve element through the leak hole or port -i in the end ot the valve element. Preferably, the end walls A of the valve casing are detachably connected to the cylindrical wall of said casing by externally screwhreaded portions on said end Walls that are screwed into the ends of the cylindrical wall of the easing, as shown in Figure 3.

Normally, the valve element B is maintained in one or the other of its extreme positions, i. e., with the port 3 in same in registration with the pipe D, as shown in Figure 8, or with the pipe E. lVhen the valve element occupies the position shown in Figure 3, the exhaust passageway E2 in the ext rior of said valve element registers with the exhaust port E in the valve casing and the pipe E that leads from the valve to the cylinder of the piston which the valve controls. If the equilibrium in the internal pressure of the casing is destroyed by reducing the pressure in the right-hand end of the valve casing, the valve element B will shift or move into its other extreme position, thus changin the relationship between the ports or passageways in the valve element and the co-operating ports or passageways in the valve casing. "Various means may` be used'to produce an unbalanced condition in the pressure of the operating medium in the valve casing. so as to eflect a change in the position of the valve element B, but I prefer to arrange vent valves or venting devices `F andfGr in the end walls ofthe valve casing for venting either endof the valve casing, said vent valves being preferably of such design that the internal pressure in the valve casing will tend to hold said valve seated and being equipped with stems F and G for actuatingr or unseating said valves. Springs 6 are preferably combined with the stems ot the vent valves so as to insure said valves normally remaining in a seated condition, and removable caps 7 are provided so as to house the springs of the vent valves and impart a neat and ornamental appearance to thevalve structure. Any other suitable type or kind of meansmay be provided for venting the end portions of the valve casing, but I have found that vent valves F and G of the kind herein illustrated are inexpensive to construct and are reliable in operation.

As previously stated, when thervalve element B is in the position shown in Figure 3, the operating medium will pass from the source of supply through the pipe D, into one end of the cylinder with which the valve is associated, and the opposite end of said cylinder will then be indirect communication with the atmosphere through the pipe E, eX- haust passageway E2 in the exterior of the valve element and the exhaust port E in the valvecasing. If it is desired vto admit the operating medium to the opposite end of said cylinder, the stem G of the vent valve G is pushed inwardly so as to permit the operating medium-in the right hand end of the valve casing toescape from saine through the port controlled by the vent valve G, thereby, causing the valve element B tomoveto the right into its other,` extreme position, due to the greater pressure whichthe operating medium exerts on the left hand end of said valve element, as soon as the right hand end of the valve casing is vented. This movement ofA the valve element Bte the right, looking at Figure 3, cuts ofi' communication between the source of supply of the operating medium and the pipe Dcuts off communicationV between the exhaust-passageway E2 inthe exterior of the valve element and the pipe E, establishes communication betweenv the source of supply ofthe operating mediumiand the pipe E, through the port 3 in the valve element, and also establishes communication between the pipe D and the exhaust, port D in the valve casing through the passageway D2 in the exterior of the valve. Itv will thus be seen that the simple act yof pushing inwardly on the stem of the vent valve Gr instantly effects a change inthe position ofthe valvev element, with the result that the operating medium is admittedto the other end of thecylinder with which the valve isy associated,

thereby causing the piston in saidcylinder tor ifforeie ing suliiciently to reduce the pressure on the right hand end of the valve element, Whereupon said valve element moves to the right, due to the greater pressure which the operating medium exerts on the lett hand end ot same, the port which the vent valve G controls being of considerably greater area than the area of the port l in the right hand end Wall of the valve element, so as to cause the operating medium to escape from the right hand end ot the valve casing at a higher rate than the operating medium can enter the right hand end of the casing trom the interior of the valve element through the port 4 in the right hand end of said element. TW hen it is desired to restore the valve element to its former position itis only necessary to unseat the vent valve F so as to reduce the pressure on the left hand end oi' the valve element B, whereupon said valve element will move to the left back to its former position.

`While I have herein illustrated my invention embodied in a valve that is intended to be used in conjunction With a double acting piston to control the admission and exhaust of an operating medium to and from the opposite ends of the cylinder in which said piston reciprocates, l Wish it to be understood that my invention is not limited to a control valve for a double acting piston, as the valve can be used equally Well with a single acting piston, i. e., a piston that is moved in one direction by an operating medium under pressure, and moved in the opposite direction by a spring or other suitable means, by simply omitting or closing up one or the other of the pipes D or E that lead :from the casing of the valve to the device which the valve controls. ln such an installation the admission of the operating medium to the cylinder of the device With Which the valve is associated is effected by uns/eating the vent valve in one end of the valve casing, and the exhaust of the operating medium from said cylinder is effected by unseating the vent valve in the opposite end of the valve casing A My valve is capable of various uses, but it is particularly adapted for use in controlling the operation of machines of the type that comprise a part which is moved in one direction by admitting an operating` medium to one end of a cylinder provided With a piston that is operatively connected to said part, and moved in the opposite direction by admitting the operating medium to the opposite end of said cylinder. 0bviously, the vent valves Which are used to unbalance or destroy the equilibrium of the pressure in the valve casing may be operated manually or by a means that operates automatically in vconjunction vvith the machine or device that the valve controls, andir" desired, the pipes D and E that are attached to the valve casing may be combined With headers from Which groups of pipes lead to a plurality of cylinders.

Having thus described my invention, what l claim as new and desire to secure by Letters Patent is A control valve, comprising a casing pro-V vided With a supply port and with an exhaust port, a hollow valve element reciprocatingly mounted in said casing, a device positioned in an elongated slot in said element for admitting an operating medium under pressure to the interior of said valve element, a port in SAMUEL B. CLAY. 

